National Institutes of Health Director Dr. Francis Collins told CNN that when the world eventually gets a coronavirus vaccine, it might require two doses to be fully effective.
“Obviously that’s not our favorite. It would be much better if this could all be done with a single injection,” Collins said.
Generally, with any vaccine, one dose is preferred for cost reasons, and also because people are less likely to show up twice to receive an injection.
Collins said the large-scale clinical trials of several experimental vaccines, expected to start next month, will reveal whether one or two doses will be necessary.
“There is certainly a chance that one or more of these vaccines might turn out to require two shots in order to get full immune response. That’s one of the reasons to do the experiments and the research trials to find that out,” he said. “If what it takes to provide full protection for any of these is two doses, we want to know that.”
The US Biomedical Advanced Research and Development Authority (BARDA), a part of the Department of Health and Human Services, is currently funding research on five different experimental vaccines. Pharmaceutical companies Moderna and AstraZeneca are currently in clinical trials, testing the vaccines on humans. Johnson & Johnson, Sanofi, and Merck are developing a vaccine, but have not yet started clinical trials, according to the World Health Organization.